Non-aqueous liquid electrolyte and lithium secondary battery comprising the same

Abstract

The present disclosure provides a lithium secondary battery comprising a non-aqueous liquid electrolyte comprising lithium bis(fluorosulfonyl)imide (LiFSI) and a trimethylsilyl phosphate (TMSPa) additive, a positive electrode comprising a lithium-nickel-manganese-cobalt-based oxide as a positive electrode active material, a negative electrode and a separator.The non-aqueous liquid electrolyte for a lithium secondary battery of the present disclosure is capable of forming a solid SEI membrane in the negative electrode when initially charging a lithium secondary battery comprising the same, is capable of improving an output property of the lithium secondary battery, and is also capable of enhancing an output property and a capacity property after high temperature storage.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT / KR2015 / 010243 filed Sep. 25, 2015, published in Korean, which claims priority from Korean Patent Application No. 10-2014-0128885, filed Sep. 26, 2014, the disclosures of which are incorporated herein by reference.FIELD OF THE INVENTIONTechnical Field[0002]The present disclosure relates to a lithium secondary battery comprising a non-aqueous liquid electrolyte comprising lithium bis(fluorosulfonyl)imide (LiFSI) and a trimethylsilyl phosphate (TMSPa) additive, a positive electrode comprising a lithium-nickel-manganese-cobalt-based oxide as a positive electrode active material, a negative electrode and a separator.Description of the Related Art[0003]With increases in technology developments and demands for mobile devices, demands for secondary batteries as an energy source have rapidly increased, and among such secondary batteries, li...

AI Technical Summary

Benefits of technology

The patent text describes a non-aqueous liquid electrolyte for a lithium secondary battery that forms a solid SEI membrane in the negative electrode when initially charging the battery. This electrolyte improves the battery's output and capacity when stored at high temperatures.

Problems solved by technology

In existing technologies, enhancement in the low temperature output property has been difficult to be expected in a liquid electrolyte that does not comprise a liquid electrolyte additive or comprises a liquid electrolyte additive having poor properties due to the formation of a non-uniform SEI membrane.

Moreover, even when a liquid electrode additive is comprised but the amounts of the additive added are not adjusted to required amounts, there has been a problem in that a positive electrode surface is decomposed in a high temperature reaction due to the liquid electrolyte additive, or the liquid electrolyte causes an oxidation reaction and ultimately, irreversible capacity of a secondary battery increases and an output property declines.